Search results for "multiplexing"
showing 10 items of 179 documents
Performance analysis of Alamouti-coded OFDM systems over spatio-temporally correlated underwater acoustic channels
2017
In this paper, we analyze the performance of Alamouti-coded orthogonal frequency division multiplexing (OFDM) systems over time-varying underwater acoustic (UWA) channels. A realistic UWA channel model has been considered, which can be correlated in either time or space or simultaneously in both domains. An exact analytical expression for the bit error probability (BEP) is necessary to analyze accurately the performance of Alamouti-coded OFDM systems over the spatio-temporally correlated UWA channel model. Hence, by using this UWA channel model, an expression has been derived for the BEP of Alamouti-coded OFDM systems assuming that the receiver knows perfectly the channel state information.…
Multi-application Based Network-on-Chip Design for Mesh-of-Tree Topology Using Global Mapping and Reconfigurable Architecture
2019
This paper outlines a multi-application mapping for Mesh-of-Tree (MoT) topology based Network-on-Chip (NoC) design using reconfigurable architecture. A two phase Particle Swarm Optimization (PSO) has been proposed for reconfigurable architecture to minimize the communication cost. In first phase global mapping is done by combining multiple applications and in second phase, reconfiguration is achieved by switching the cores to near by routers using multiplexers. Experimentations have been carried out for several application benchmarks and synthetic applications generated using TGFF tool. The results show significant improvement in terms of communication cost after reconfiguration.
Dual-mode holographic microscopy imaging platform
2018
We report on a novel layout capable of dual-mode imaging in real time with different magnifications and resolution capabilities in lensless microscopy. The concept is based on wavelength multiplexing for providing two illuminations with different wavefront curvatures: one is collimated, allowing a large field of view (FOV) with a poor resolution limit, and the other is divergent, to achieve a better resolution limit (micron range) over a small FOV. Moreover, our recently reported concept of MISHELF microscopy [M. Sanz, J. Á. Picazo-Bueno, L. Granero, J. García and V. Micó, Sci. Rep., 2017, 7, 43291] is applied to the divergent illumination case, improving the image quality by noise averagin…
Contributions to Phase Two of AGATA electronics
2020
En el campo de la física nuclear, la espectroscopia de rayos gamma de alta resolución es un método preciso para estudiar la estructura del núcleo, extrayendo la energía y la distribución angular de los fotones gamma emitidos en las transiciones entre estados nucleares. Para obtener núcleos en un estado excitado y por tanto emitan rayos gamma, hemos de hacer chocar la materia, produciendo reacciones nucleares (espectroscopia de haz) o recurrir a desintegraciones radiactivas (espectroscopia de desintegración). Los detectores de semiconductor de germanio de alta pureza (HPGe) han demostrado tener una buena respuesta interaccionando con rayos gamma. Al igual que otros detectores de basados en s…
Multiplexed plasmon sensor for rapid label-free analyte detection.
2013
Efficient and cost-effective multiplexed detection schemes for proteins in small liquid samples would bring drastic advances to fields like disease detection or water quality monitoring. We present a novel multiplexed sensor with randomly deposited aptamer functionalized gold nanorods. The spectral position of plasmon resonances of individual nanorods, monitored by dark-field spectroscopy, respond specifically to different proteins. We demonstrate nanomolar sensitivity, sensor recycling, and the potential to upscale to hundreds or thousands of targets.
Applicability of Interference Coordination in Highly Loaded HSUPA Network
2010
This paper evaluates the performance of highly loaded High Speed Uplink Packet Access (HSUPA) network with and without network wide static Interference Coordination (IC). IC alternates the priorities for user transmission periods throughout the network to achieve reduced interference levels and higher performance. A large variety of combinations including, e.g., different schedulers, cell center/edge user definitions (user splits) and interference targets are investigated in this paper. Performance is analyzed using a quasi-static system level simulator which is also used to support Third Generation Partnership Project (3GPP) standardization work. The simulator contains detailed and commonl…
BIO-Bragg gratings: structured molecular networks for on-fiber bioanalysis
2021
The research on photonic biosensors is a scientific hot topic at the moment, with a significant potential impact on industry and medicine. Label-free, miniaturized, inexpensive and low-loss biosensors are developed based on optical fiber technology. Our approach is based on a Bio-Bragg-Grating (BBG) patterned on the surface of a microfiber. We present the design, fabrication and proof of concept of our device, as well as its multiplexing and tunability perspectives [1] .
Channel Estimation and Interference Cancellation for MIMO-OFDM Systems
2007
This paper proposes a new channel estimation method and a new interference cancellation scheme for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems in the presence of intersymbol interference (IS1). The proposed channel estimation method uses special training sequences (TSs) to have a desirable crest-factor of the transmitted training signal, and to prevent the influence of ISI on the channel estimation performance. By using the recommended training sequences, the ill-conditioned problem of the least square (LS) filter integrated in the proposed channel estimator can be avoided. The proposed interference cancellation scheme uses the estimated cha…
Performance Analysis of STBC-OFDM Systems in Temporally or Spatially Correlated Fading Channels
2010
This paper analyzes the performance of space-time block coded orthogonal frequency division multiplexing (OFDM) systems. In our analysis, we abandon the usually made assumption of quasi-static channel conditions. Instead of this, we consider the more general and realistic case that the channel envelope changes during two consecutive transmission time slots. In addition, we take the spatial correlation between sub-channels into account. We first present a general formal expression for the bit error probability (BEP), from which we find analytical solutions for the BEP not only for temporally fading channels but also for spatially correlated channels. The knowledge of the obtained analytical …
Channel aggregation with guard-band in D-OFDM based CRNs: Modeling and performance evaluation
2016
Channel aggregation (CA) techniques can offer flexible channel allocation and improve overall system performance in multi-channel cognitive radio networks (CRNs). Although many CA techniques have been proposed and studied, the impact of guard-band on CA for channel access has not been addressed in-depth. In this paper, we study the guard-band allocation mechanisms in discontinuous-orthogonal frequency division multiplexing (D-OFDM) based CRNs, and investigate the impact of guard-band sharing on SU flows when CA is enabled. Continuous time Markov chain (CTMC) based models have been developed in order to investigate the stochastic behavior of PU and SU flows. Based on our mathematical analysi…